1. Field
Example embodiments may relate to data storage devices, for example, to data storage devices that can record, store, and/or erase data by moving magnetic domain walls in a magnetic material.
2. Description of the Related Art
Related art data storage devices with high speed and/or compact size have been developed. In general, a hard disk drive (HDD), which may be used as a data storage device, may include a reading/writing head and/or one or more platters in which data may be recorded. Related art HDDs may store large amounts of data of 100 gigabyte (GB) or more. Related art HDDs may have degraded performance due to wear and may malfunction as a result. Reliability of related art HDDs may be lowered as a result.
Related art data storage devices may use movement of magnetic domain walls in a magnetic material to increase reliability.
FIGS. 1A and 1B are schematic views illustrating the moving principle of magnetic domain walls in related art storage devices. As shown in FIG. 1A, a magnetic wire may include a first magnetic domain 11, a second magnetic domain 12, and/or a magnetic domain wall 13 as a boundary between the first and second magnetic domains 11 and 12.
In general, minute magnetic regions within a magnetic body are called magnetic domains. In a magnetic domain, the movement of electrons, that is, the direction of the magnetic moment, may be substantially uniform. Size and magnetization direction of the magnetic domains may be controlled by the shape and/or size of the magnetic material and/or external energy applied thereto. A magnetic domain wall may be a boundary of magnetic domains having different magnetizations. The magnetic domain wall may be moved by a magnetic field and/or a current applied to the magnetic material.
As shown in FIG. 1A, after forming a plurality of magnetic domains having a magnetic moment in a first magnetic layer having a determinable width and thickness, a magnetic domain wall may be moved by applying an appropriate magnetic field and/or a current from the outside.
As shown in FIG. 1B, if an external current is applied to the first magnetic layer in the direction away from the first magnetic domain 11 toward the second magnetic domain 12, the magnetic domain wall 13 may move toward the first magnetic domain 11. If an opposite current is applied, electrons may flow in the opposite direction, and the magnetic domain wall 13 may be moved in the same direction as the electrons. That is, the magnetic domain wall 13 may move in the opposite direction to the direction in which the external current is applied. If a current is applied away from the second magnetic domain 12 toward the first magnetic domain, the magnetic domain wall 13 may be moved away from the first magnetic domain 11 toward the second magnetic domain 12. Thus, the magnetic domain wall 13 may be moved by applying an external magnetic field or a current, thereby moving the magnetic domains 11 and 12.
The moving principle of a magnetic domain wall may be applied to data storage devices, for example, a HDD or a non-volatile RAM. A non-volatile memory device that may write and/or read data as ‘0’ or ‘1’ may be created using the principle that voltage in a linear magnetic material may be varied based on movement of a magnetic wall in the material having magnetic domains magnetized in particular directions and magnetic domain walls therebetween. Data may be written and/or read by changing the position of magnetic domain walls by applying a current to the linear magnetic material, and thus a higher integrated device having a simpler structure may be fabricated. By using the moving principle of the magnetic domain wall, a memory device with increased storage capacity over related art FRAMs, MRAMs, and/or PRAMs can be manufactured.